Think about this: Microsoft spent a fair amount of resources integrating with gtalk, now they can't use it. The only way for them to gain access is to open up their own platforms. Once they do, then everyone is on a more level playing field.
The days of Microsoft shafting the competition through lock-in and anti-competitive behaviour is fast coming to an end. I'm not shedding any tears.
So rather than waiting for Google to become the 'bigger man' (or Microsoft for that matter), which will likely never happen, I will move onto other services, because - fortunately - I have a choice.
My argument being, that if someone is trying to stop me changing services, because I am unhappy about the fact that Google are dropping or federalising their XMPP services, then 'Microsoft is doing the same thing' isn't the argument that is going to send me back to Google.
Why would Google want to invest resources on giving Microsoft an unfair advantage over themselves? Microsoft being jerks is the rule since that open letter Bill Gates sent to the Homebrew Computer Club.
In other words, why would you invite a guest that is known to steal stuff and not flush toilets into your home?
Because it's good for the users.
I prefer it when someone showcases their willingness to be 'the nicer guy' by opening up while the others are closing down. Like allowing to export your GMail contacts, while Facebook won't go the other way around.
I always find Microsoft complaining to be hypocritical, they are usually committing a similar overreach towards a competitor themselves. But still, where are the 'good guys'?
I know, that would be naïve, this is business.